Bats have a conveyor-belt tongue
Nectar-feeding bats turn their tongues into the equivalent of a conveyor belt to drink from flowers, a new study has revealed.
Most bat species lap-up nectar using elongated tongues, which can exceed even the length of the bat's body. Their tongues are covered in long hair-like "papillae" which help to pick up the nectar as the bats lift it from flowers. This brush-like lapping is the same technique used by ants and bees.
However, the never-before-seen eating habits of the Lonchophylla bat show a different way of getting hold of the sweet stuff. These bats don't lap up the nectar, but instead use a special grooved tongue to pump nectar straight into their mouths.
Using high-speed cameras, researchers based in in Germany and Panama, writing in Science Advances, compared the eating habits of two different bat species as they hovered at a series of artificial 'test tube' flowers for around a second. In this short time they were caught on camera extracting honey water from the feeders.
In the first species, the cameras captured the bats' tongues dipping in and out of the feeder while they lapped at the nectar, like a cat might lap up milk. In the Lonchophylla species, on the other hand, the bats' tongues remained in the nectar for its whole feed.
The scientists think that this is because Lonchophylla bats use complex bundles of muscles as well as capillary action to actively "pump" nectar up through its grooved tongue and into its mouth. This kind of feeding had never been observed before.
The scientists were also able to calculate and compare the efficiency of both techniques. After accounting for size differences between the species, the Lonchophylla bat, with its conveyer belt-like tongue, was the clear winner. Although the scientists pointed out that the artificial flowers used in the study could have favoured this type of feeding.
Nectar is a valuable resource for animals. It consists of various sugars and is a highly sort after energy source. However, when it comes to searching out nectar most mammals are opportunistic; and so don't have special adaptations to assist them doing this.
Any specialised nectar feeding mechanisms within mammals usually resemble either the lapping of a cat, or sucking-up, as though through a straw.
This latest discovery reveals a third, conveyor belt-like mechanism used by bats to extract nectar from flowers.
How this mechanism works, is still not fully understood, but scientists think that this might be an adaptation which is particularly suited to certain flowers.